There is a chiyuv to give maaser from your income. If you receive an expensive mishloach manos, do you need to give maaser from it? This was the question asked to Rav Ephraim Greenblatt (Rivevos Ephraim 6:389), rov in Memphis and talmid muvhak of Rav Moshe Feinstein zt”l.
Rav Greenblatt answered that he saw in a sefer, called Uvacharta Bachaim, that Rav Chaim Kreiswirth, the Antwerpen rov, said in a hesped for Rav Yaakov Kamenetzky zt”l, that Rav Yaakov would report as income and pay taxes on mishloach manos that he received. If so, then similarly one should give maaser. He concludes by saying that nevertheless the matter needs further research.
Titein emes l’Yaakov!